1. Field of the Invention
The present invention relates in general to mineral recovery wells, and in particular to lockdown rings for retaining wellbore members in a housing.
2. Brief Description of Related Art
In wellheads used for recovery of minerals, such as hydrocarbons, it is common to land a tubing hanger in the wellhead housing. An annular seal is usually inserted in the annulus between the wellhead housing and the tubing hanger for the purpose of sealing the annulus, thus preventing fluids from escaping the annulus toward the wellhead. With some types of seals, an energizing ring is urged against the seal to cause the seal to expand and sealingly engage an adjacent surface. With a u-shaped seal, for example, an energizing ring can be forced into the gap between the legs of the u-shaped seal to urge the legs outward and engage the inner diameter of the wellhead housing and the outer diameter of the tubing hanger.
During wellbore operations, high pressure conditions can occur. The high pressure can exert upward force on the tubing hanger. Significant force can urge the tubing hanger upward from its position in the wellhead housing. The energized seal can help hold the tubing hanger in position. Unfortunately, the force and positional shifting of the tubing hanger can urge the energizing ring upward, away from its position within the sealing ring. Once the energizing ring has shifted to the point that the seal is no longer energized, the seal can fail and allow further movement of the tubing hanger relative to the casing hanger. Such a failure can be catastrophic. It is desirable to hold the energizing ring in position within the sealing ring so that the energizing ring cannot shift in response to upward force on the tubing hanger.